A general solid-state imaging device includes an embedded photodiode as a photoelectric conversion unit.
Moreover, Patent Literature 1 (PTL 1) discloses a stacked solid-state imaging device. In this stacked solid-state imaging device, a photoelectric conversion film is formed on a control electrode and, a transparent electrode layer is formed on the photoelectric conversion film. The stacked solid-state imaging device can convert light information into an electric signal at an excellent signal-to-noise (SN) ratio by giving effects obtained from a voltage applied to this transparent electrode to the control electrode via the photoelectric conversion film.
In the stacked solid-state imaging device, a photoelectric conversion film is formed above a semiconductor substrate on which a pixel circuit is formed, via an insulating film. Thus, a material having a large optical absorption coefficient such as amorphous silicon can be used for the photoelectric conversion film. For instance, when the amorphous silicon is used for the photoelectric conversion film, most of green light having a wavelength of 550 nm can be absorbed by a photoelectric conversion film having a thickness of around 0.4 nm.
Moreover, the stacked solid-state imaging device does not include an embedded photodiode. This allows to increase the capacity of the photoelectric conversion unit in the stacked solid-state imaging device. Therefore, saturated charges can be increased. Furthermore, since charges are not completely transferred in the stacked solid-state imaging device, it is possible to facilitate the addition of capacitance. This can achieve sufficient capacitance also in a miniaturized pixel of the stacked solid-state imaging device. Furthermore, a configuration as the stack cell in a dynamic random access memory can be employed in the stacked solid-state imaging device.